after sharing your data, you might say that children who are struggling often confuse being bored with being frustrated and wanting to avoid doing things are are hard for them. You might want to have some work for comparison with student names hidden. Two or three class average pages along with an advanced child and an also struggling child or two to give the mom a basis of comparison. That also lets her know that her child is not alone in needed to work harder on math.

Talk about the ways you are helping in class and suggest some activities the child can do at home in a game-like way that would be helpful. I'm sure you have some of those sorts of materials or books to recommend. For on-line help, I strongly recommend the National Council of Teachers of Mathematics Illuminations to support various grade levels in math learning.

https://illuminations.nctm.org